木质素-1-丁基-3-甲基咪唑氯盐水溶液的流变特性

Rheological properties of lignin in 1-butyl-3-methylimidazolium chloride aqueous solutions

利用旋转黏度计考察木质素-1-丁基-3-甲基咪唑氯盐水溶液的流变特性,研究木质素质量分数、离子液体质量分数、剪切速率及温度对木质素溶液黏度和大分子链构型的影响。结果表明,随着木质素质量分数增大,溶液的黏度升高;温度和离子液体质量分数改变,划分木质素大分子在溶液中存在状态变化区域的特征量重叠质量分数和缠绕质量分数也发生变化。离子液体质量分数增大,木质素溶液的黏度变化趋势更显著。大部分木质素溶液具有典型剪切变稀的特征,说明剪切力作用下木质素大分子链随流体取向运动,并发生解缠结;温度升高时,木质素溶液的黏度降低;木质素或离子液体质量分数增大,黏流活化能升高,木质素分子链段克服位垒所需能量也升高。

The rheological behaviors of lignin in 1-butyl-3-methylimidazolium chloride aqueous solutions were investigated using a rotary viscosimeter.The effects of mass percentages of lignin or ionic liquid,shear rate and temperature on the viscosity and macromolecular chain configuration of lignin solution were also studied.The results showed that the viscosity of the aqueous solutions was increased with increasing mass percentage of lignin,while the mass percentages of overlapping and winding,responding to divisions of lignin macromolecules existence state,were varied with changing in the temperature and mass percentage of ionic liquid.Increasing the mass percentage of ionic liquid would generate a more obvious change in the viscosity of lignin solutions.Most of the lignin solutions had shear thinning behavior,suggesting that the macromolecular chains of lignin moved with orientation to the fluid and disentangled under the shear force.The viscosity of lignin solutions decreased with an increase of the temperature,and the viscous activation energy was enhanced with elevating in the mass percentages of lignin or ionic liquid.Additionally,the energy need to overcome the barrier in macromolecules of lignin was also enhanced.